JP6690047B1 - Friction transmission belt and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the strength of a joint portion of a knitted cloth (reinforcing cloth) covering the surface of a compression layer of a friction transmission belt. SOLUTION: The surface of a compression layer 4 (rib portion 2) of a V-ribbed belt 1 (friction transmission belt) is covered with a knitted fabric 6, and this knitted fabric 6 has one end and the other end thereof. Have overlapping portions 62, and the overlapping portion 62 has a bonding region 63 for bonding the upper surface side of one end of the knitted fabric 6 and the lower surface side of the other end. [Selection diagram] Fig. 6

Description

  The present invention relates to a friction transmission belt in which the surface of a compression layer is covered with a knitted fabric, and a method for manufacturing the friction transmission belt.

  Friction transmission belts are widely used for driving auxiliary machinery of automobiles and for driving agricultural machinery. Examples of the friction transmission belt include a flat belt, a V-belt, and a V-ribbed belt. The friction transmission belt includes a toothed belt that transmits power by mechanically fitting the tooth portion of the pulley and the tooth portion of the belt. It is used separately from the meshing transmission belt. Among them, the V-ribbed belt is widely used for driving an auxiliary machine of an automobile because it can achieve both high transmission capacity and bending fatigue resistance.

  Some V-ribbed belts have a friction transmission surface coated with a reinforcing cloth in order to improve wear resistance and adjust the friction coefficient. A woven fabric, a knitted fabric, a non-woven fabric, or the like can be applied to the reinforcing cloth, and various fibers can be used as the fibers constituting these reinforcing cloths in accordance with the requirements such as abrasion resistance and water absorption.

  For example, in Patent Document 1, the rib surface (friction transmission surface) is covered with a canvas (reinforcing cloth), the canvas is stretchable in two predetermined directions, and the canvas is an elastic yarn and at least one non-elastic yarn. V-ribbed belts, characterized in that the inelastic yarn comprises cellulose-based fibers or yarns. As a canvas (reinforcing cloth) used for such a belt, a seamless or seamed tubular canvas is exemplified (see paragraph 0020 of Patent Document 1).

  Generally, the reinforcing cloth is subjected to an adhesive treatment in order to enhance the adhesiveness with the rubber composition of the belt body. At that time, in the seamless tubular canvas illustrated in Patent Document 1, continuous adhesion cannot be applied, so that productivity is reduced, and a seamless tubular canvas having a circumference corresponding to the belt length is provided. Since it is necessary to prepare it, there is a problem that the number of work in process increases.

  Therefore, in order to enable continuous bonding of the reinforcing cloth and improve productivity, a long reinforcing cloth that allows continuous bonding is subjected to bonding processing, and reinforcement after finishing the bonding processing is performed. It has been practiced to fabricate a tubular reinforcing cloth by seaming (joining) the cloth. In this case, thermal welding or ultrasonic welding has been used as a method for joining the reinforcing cloths.

Special table 2010-533394 gazette

  However, when joining by heat welding or ultrasonic welding, the strength of the reinforcing cloth (knitted fabric) is insufficient because the edges of the reinforcing cloth (knitted fabric) are in contact with each other, and cracks occur at the joints, or cracks are used as starting points for reinforcement. There is a risk that the cloth may peel from the rib surface. In addition, since the fibers are melted and solidified in the joined portion by welding, the elasticity of the reinforcing cloth is reduced. At the joint portion of the reinforcing cloth with reduced elasticity, stress concentrates when the belt is bent, so that the rubber forming the rib portion may be easily cracked. Therefore, it has been required to improve these problems.

  Then, the subject of this invention is improving the intensity | strength of the joining part of the knitted fabric (reinforcing cloth) which coat | covers the compression layer surface of a friction transmission belt.

In order to solve the above problems, the friction transmission belt of the present invention is a friction transmission belt having a compression layer and a knitted fabric,
The compression layer surface is covered with the knitted fabric,
The knitted fabric has an overlap portion in which one end of the knitted fabric and the other end overlap with each other,
It is characterized in that the overlapping portion has an adhesive region containing an adhesive component for adhering one end of the knitted fabric and the other end thereof.

  When the knitted fabric that covers the surface of the compression layer of the friction transmission belt is joined by butt joints that do not have overlapping portions, it is difficult to sufficiently increase the strength of the joined portion of the knitted fabric and cracks occur at the joined portion. As a result, the knitted fabric is easily separated from the surface of the compression layer. Further, even when the knitted fabric has an overlapping portion, if there is no adhesive region, the strength of the joint portion of the knitted fabric is not sufficient only by the adhesive component contained in the knitted fabric, and the knitted fabric also has a compression layer. Easy to peel off from the surface. Therefore, in the overlapping portion, by providing an adhesive region containing an adhesive component for adhering one end of the knitted fabric and the other end (between the upper surface side of one end and the lower surface side of the other end), It can be reinforced so that the knitted fabric is less likely to peel from the surface of the compression layer.

  Further, in the friction transmission belt according to the present invention, the overlap portion may further include a non-adhesion region where one end of the knitted fabric and the other end thereof are not adhered.

  When the entire overlap portion where one end of the knitted fabric and the other end overlap each other is the bonded region and there is no non-bonded region, the knitted fabric is strongly restrained, and the stretchability is reduced. As a result, when the friction transmission belt is bent, stress concentrates on the joint portion of the overlap portion, and cracks are likely to occur in the compression layer. Therefore, by providing a non-adhesive region together with the adhesive region in the overlap portion, while sufficient adhesive force between one end of the knitted fabric and the other end, stress concentration is relaxed and cracks in the compression layer Occurrence can be suppressed. As a result, the belt life is improved.

Further, the present invention provides the above friction transmission belt,
You may have a plurality of the adhesion areas,
Each adhesive region may be discontinuously arranged in the belt width direction.

  According to the above configuration, when the adhesive area is arranged in the overlap portion, the non-adhesive area is always arranged in the belt width direction in which the adhesive area is arranged. It is possible to alleviate the concentration of stress over the entire belt width direction at a specific location and suppress the occurrence of cracks in the compression layer.

Further, the present invention provides the above friction transmission belt,
You may have a plurality of the adhesion areas,
You may have several said non-adhesion area | region,
The plurality of adhesive areas and the plurality of non-adhesive areas may be arranged in a checkered pattern.

  According to the above configuration, since the adhesive regions and the non-adhesive regions are alternately arranged in a checkerboard pattern, stress is concentrated over the entire belt width direction at a specific position in the belt longitudinal direction of the overlapping portion. Can be alleviated and the occurrence of cracks in the compression layer can be suppressed.

Further, the present invention provides the above friction transmission belt,
The bonding area may be wavy or lightning.

  According to the above configuration, since the adhesive areas are arranged in a wavy or lightning pattern, the adhesive areas and the non-adhesive areas are alternately arranged in the overlapping portion, and the specific portion in the belt longitudinal direction of the overlapping portion. In the above, it is possible to relieve the concentration of stress over the entire belt width direction and suppress the occurrence of cracks in the compression layer.

Further, the present invention provides the above friction transmission belt,
The total area of the adhesive region may be 10 to 50% of the area of the overlapping portion.

  If the total area of the adhesive region is less than 10% of the area of the overlap portion, the strength of the joint portion of the overlap portion of the knitted fabric cannot be sufficiently increased, and cracks occur at the joint portion, resulting in knitting. The cloth may peel off from the surface of the compression layer. On the other hand, when the total area of the bonding area is larger than 50% of the area of the overlapping portion, the knitted fabric is restrained more than necessary, the elasticity is reduced, and the overlapping portion is joined when the friction transmission belt is bent. There is a risk that stress concentrates on the portion and cracks are likely to occur in the compression layer. Therefore, by setting the total area of the adhesive region to 10 to 50% of the area of the overlapping portion, the strength of the joint portion of the overlapping portion can be sufficiently increased, while the elasticity of the knitting cloth can be maintained, It is possible to prevent the peeling from the surface of the compression layer and the generation of cracks in the compression layer in a well-balanced manner.

Further, the present invention provides the above friction transmission belt,
The knitted fabric may be impregnated with isocyanate.

  By impregnating the knitted cloth with isocyanate, it is possible to improve the abrasion resistance and the adhesiveness of the overlap portion.

Further, the present invention provides the above friction transmission belt,
In the bonding area, one end and the other end of the knitted fabric may be bonded by an adhesive component excluding the isocyanate.

  According to the above configuration, the knitted fabric is impregnated with isocyanate in order to improve wear resistance and adhesiveness, and further, in the adhesive region, an adhesive component different from the isocyanate impregnated in the knitted fabric is used. As a result, a sufficient adhesive force can be secured at the joined portion of the overlapping portion, and the knitted fabric can be prevented from peeling from the surface of the compression layer starting from the overlapping portion.

Further, the present invention provides the above friction transmission belt,
The adhesive component may include a thermoplastic elastomer.

  When a thermoplastic elastomer is used as the adhesive component, the generation of cracks in the compression layer can be suppressed more than when a rubber composition is used as the adhesive component in the adhesive region.

Further, the present invention provides the above friction transmission belt,
The thermoplastic elastomer may be thermoplastic polyurethane.

  The production cost can be reduced by using a highly versatile thermoplastic polyurethane as the thermoplastic elastomer used as the adhesive component in the adhesive region.

Further, the present invention provides the above friction transmission belt,
The thermoplastic elastomer may have a flow starting point of 100 ° C. or higher and 160 ° C. or lower.

If the flow starting point of the thermoplastic elastomer is less than 100 ° C., the strength of the adhesive region may be reduced during use of the friction transmission belt, and the knitted fabric may be easily peeled off. Further, when the flow starting point of the thermoplastic elastomer is 160 ° C. or lower, the thermoplastic elastomer is softened during vulcanization of the friction transmission belt, the adhesion with the knitted fabric is improved, and the adhesive force can be improved. On the other hand, when the flow starting point is higher than 160 ° C., the above effect cannot be obtained and the adhesive force may not be sufficiently improved. Therefore, it is preferable that the flow starting point of the thermoplastic elastomer used in the adhesion region is 100 ° C. or higher and 160 ° C. or lower.
The flow starting point can be measured using a Koka type flow tester (extrusion type plastometer) described in JIS K7210-1 (2014). A cylinder equipped with a die having a hole with an inner diameter of 1 mm and a length of 10 mm is filled with about 2 g of thermoplastic elastomer and a load of 294 N is applied. The temperature is raised from the initial temperature of 100 ° C. at a rate of 6 ° C./min, and the temperature at which the thermoplastic elastomer begins to flow out from the die is taken as the flow starting point.

  Further, in the friction transmission belt according to the present invention, the adhesive component may include cellulose nanofibers.

  In this case, the durable life can be improved as compared with the case where the adhesive component does not contain cellulose nanofibers.

Further, the present invention provides the above friction transmission belt,
The length of the overlapping portion in the belt circumferential direction may be 2 mm or more and 10 mm or less.

  If the length of the overlapping portion in the circumferential direction of the belt is less than 2 mm, the strength of the joint portion may be insufficient, and the joint portion may be cracked or the knitted fabric may be easily peeled off. On the other hand, if the length of the overlap portion in the circumferential direction of the belt exceeds 10 mm, the influence of the step of the overlap portion becomes large, and there is a possibility that problems such as deterioration of appearance quality and abnormal noise or tension fluctuation may occur. Therefore, the length of the overlapping portion in the belt circumferential direction is preferably in the range of 2 mm or more and 10 mm or less.

Further, the present invention is a method for producing a friction transmission belt, wherein the compression layer surface is covered with a knitted fabric having an overlapping portion where one end and the other end overlap.
A step of applying or spraying a rubber paste obtained by dissolving the rubber composition in a solvent onto at least one of the upper side of one end of the knitted fabric and the lower side of the other end of the knitted fabric may be included.

  At least one of the upper side of one end of the knitted fabric and the lower side of the other end is coated or sprayed with a rubber paste in which a rubber composition is dissolved in a solvent to reinforce the joint portion, and the knitted fabric has a compressed layer surface. It is possible to make it difficult to peel off from.

Further, the present invention is a method for producing a friction transmission belt, wherein the compression layer surface is covered with a knitted fabric having an overlapping portion where one end and the other end overlap.
A step of disposing a sheet of the rubber composition having a thickness of 50 to 150 μm between the upper side of one end of the knitted fabric and the lower side of the other end of the knitted fabric may be included.

  Improving productivity by arranging a sheet-shaped rubber composition that is easier to handle than applying or spraying rubber paste between the upper side of one end of the knitted fabric and the lower side of the other end of the knitted fabric. You can In addition, the thickness of the sheet-shaped rubber composition is set to 50 to 150 μm to ensure sufficient adhesiveness, while minimizing the step of the overlapping portion to reduce appearance quality, abnormal noise, tension fluctuation, etc. Can be suppressed.

Further, the present invention is a method for producing a friction transmission belt, wherein the compression layer surface is covered with a knitted fabric having an overlapping portion where one end and the other end overlap.
The method may include disposing the molten thermoplastic elastomer between the upper side of one end of the knitted fabric and the lower side of the other end of the knitted fabric.

  A thermoplastic elastomer can be disposed between the upper side of one end of the knitted fabric and the lower side of the other end of the knitted fabric while freely controlling the shape and amount by utilizing the thermoplastic property.

  The strength of the joint portion of the knitted fabric (reinforcing fabric) that covers the surface of the compression layer of the friction transmission belt can be improved.

FIG. 1 is a schematic perspective view illustrating an example of a belt transmission device using a V-ribbed belt according to this embodiment. FIG. 2 is a cross-sectional view of the V-ribbed belt taken along the line AA ′ of FIG. FIG. 3 is an explanatory view showing an overlapping portion of the knitted fabric in the V-ribbed belt according to the present embodiment. FIG. 4 is an explanatory view showing the overlapping portion of the knitted fabric in the V-ribbed belt according to this embodiment. FIG. 5: is explanatory drawing which shows the overlapping part of the knitted fabric in the V ribbed belt which concerns on this embodiment. FIGS. 6A to 6C are explanatory views exemplifying aspects of the adhesion region and the non-adhesion region in the overlap portion. FIG. 7A and FIG. 7B are explanatory views exemplifying modes of the adhesion region and the non-adhesion region in the overlap portion. FIGS. 8A to 8C are explanatory views exemplifying aspects of the adhesion region and the non-adhesion region in the overlap portion. FIG. 9A and FIG. 9B are explanatory views exemplifying modes of a bonding region and a non-bonding region in the overlap portion. 10A to 10C are conceptual diagrams for explaining the method for manufacturing the V-ribbed belt. FIG. 11 is a layout of a multi-axis running tester used in the durability test according to the example. 12: is a figure which shows the result of the endurance test which concerns on Examples 1-8. FIG. 13: is a figure which shows the result of the endurance test which concerns on Comparative Examples 1-2.

  An example of an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a belt transmission device for driving an auxiliary machine using a V-ribbed belt 1 as an example of a friction transmission belt according to the present invention. This belt transmission device is provided with a drive pulley 21 and a driven pulley 22 one by one, and is the simplest example in which the V-ribbed belt 1 is wound between the drive pulley 21 and the driven pulley 22. The endless V-ribbed belt 1 is formed with a plurality of V-shaped ribs 2 extending in the belt circumferential direction on the inner circumferential side, and the V-ribbed belt 1 is provided on the outer peripheral surfaces of the drive pulley 21 and the driven pulley 22. A plurality of V-shaped grooves 23 into which each rib portion 2 is fitted are provided.

(Structure of V-ribbed belt 1)
As shown in FIG. 2, the V-ribbed belt 1 includes a stretching layer 3 forming a belt back surface on the outer peripheral side, a compression layer 4 provided on the inner peripheral side of the stretching layer 3, a stretching layer 3 and a compression layer 4. A plurality of V-shaped rib portions 2 extending in the belt circumferential direction are formed in the compression layer 4 with a core wire 5 embedded in the belt circumferential direction, and the surface of the rib portion 2 serving as a friction transmission surface. Is covered with a knitted fabric 6 having an overlap portion 62 (see FIG. 3) in which one end and the other end are overlapped and adhered (details will be described later). The expansion layer 3 and the compression layer 4 are both formed of a rubber composition, as described later. An adhesive layer may be provided between the expansion layer 3 and the compression layer 4 if necessary. This adhesive layer is provided for the purpose of improving the adhesiveness of the core wire 5 to the extension layer 3 and the compression layer 4, but is not essential. The form of the adhesive layer may be a form in which the entire core wire 5 is embedded in the adhesive layer, or a form in which the core wire 5 is embedded between the adhesive layer and the extension layer 3 or between the adhesive layer and the compression layer 4. .

(Compression layer 4)
The rubber component of the rubber composition forming the compression layer 4 may be a vulcanizable or crosslinkable rubber, for example, a diene rubber (natural rubber, isoprene rubber, butadiene rubber, chloroprene rubber, styrene butadiene rubber, acrylonitrile butadiene rubber, hydrogen). Nitrile rubber, mixed polymer of hydrogenated nitrile rubber and unsaturated carboxylic acid metal salt), ethylene-α-olefin elastomer, chlorosulphonated polyethylene rubber, alkylated chlorosulphonated polyethylene rubber, epichlorohydrin rubber, acrylic rubber, Examples thereof include silicone rubber, urethane rubber, and fluororubber.

  Among these, it is preferable to form an unvulcanized rubber layer with a rubber composition containing sulfur or an organic peroxide, and to vulcanize or crosslink the unvulcanized rubber layer, particularly, to contain no harmful halogen, An ethylene-α-olefin elastomer (ethylene-α-olefin rubber) is preferable because it has ozone resistance, heat resistance, and cold resistance and is economically excellent. Examples of the ethylene-α-olefin elastomer include ethylene-α-olefin rubber and ethylene-α-olefin-diene rubber. Examples of the α-olefin include propylene, butene, pentene, methylpentene, hexene and octene. These α-olefins can be used alone or in combination of two or more. Further, examples of the diene monomer as the raw material include non-conjugated diene-based monomers such as dicyclopentadiene, methylene norbornene, ethylidene norbornene, 1,4-hexadiene and cyclooctadiene. These diene monomers can be used alone or in combination of two or more.

  Representative examples of the ethylene-α-olefin elastomer include ethylene-α-olefin rubber (ethylene-propylene rubber) and ethylene-α-olefin-diene rubber (ethylene-propylene-diene copolymer). In the ethylene-α-olefin elastomer, the ratio of ethylene and α-olefin (the former / latter mass ratio) is, for example, 40/60 to 90/10, preferably 45/55 to 85/15, and more preferably 55 /. The range of 45 to 80/20 is preferable. Further, the proportion of the diene can be selected from the range of 4 to 15% by mass, for example, 4.2 to 13% by mass, preferably 4.4 to 11.5% by mass. The iodine value of the ethylene-α-olefin elastomer containing a diene component is, for example, 3 to 40, preferably 5 to 30, and more preferably 10 to 20. If the iodine value is too small, vulcanization of the rubber composition will be insufficient and abrasion and sticking will easily occur, and if the iodine value is too large, the scorch of the rubber composition will be short and the rubber composition will be difficult to handle. At the same time, the heat resistance tends to decrease.

  Examples of the organic peroxide that crosslinks the unvulcanized rubber layer include diacyl peroxide, peroxyester, dialkyl peroxide (dicumyl peroxide, t-butylcumyl peroxide, 1,1-di-butylperoxy-3. , 3,5-Trimethylcyclohexane, 2,5-dimethyl-2,5-di (t-butylperoxy) -hexane, 1,3-bis (t-butylperoxy-isopropyl) benzene, di-t-butyl For example, peroxide). These organic peroxides can be used alone or in combination of two or more. Further, the organic peroxide has a decomposition temperature of, for example, 150 ° C. to 250 ° C., preferably about 175 ° C. to 225 ° C. for obtaining a half-life of 1 minute.

  The ratio of the vulcanizing agent or the crosslinking agent (particularly organic peroxide) in the unvulcanized rubber layer is, for example, 1 to 10 parts by mass in terms of solid content with respect to 100 parts by mass of the rubber component (ethylene-α-olefin elastomer etc.). Parts, preferably 1.2 to 8 parts by mass, more preferably 1.5 to 6 parts by mass.

  The rubber composition may contain a vulcanization accelerator. Examples of the vulcanization accelerator include thiuram accelerators, thiazole accelerators, sulfenamide accelerators, bismaleimide accelerators, urea accelerators and the like. These vulcanization accelerators can be used alone or in combination of two or more kinds. The ratio of the vulcanization accelerator (the total amount when a plurality of kinds are combined) is, for example, 0.5 to 15 parts by mass, preferably 1 to 10 parts by mass, and further 100 parts by mass in terms of solid content. The amount is preferably 2 to 5 parts by mass.

  In addition, the rubber composition may further contain a co-crosslinking agent (crosslinking aid or covulcanizing agent) in order to increase the degree of crosslinking and prevent adhesive wear and the like. Examples of the co-crosslinking agent include conventional crosslinking aids such as polyfunctional (iso) cyanurates (triallyl isocyanurate, triallyl cyanurate, etc.), polydienes (1,2-polybutadiene, etc.), and metal salts of unsaturated carboxylic acids. (Zinc (meth) acrylate, magnesium (meth) acrylate, etc., oximes (quinonedioxime, etc.), guanidines (diphenylguanidine, etc.), polyfunctional (meth) acrylates (ethylene glycol di (meth) acrylate, butane Examples thereof include diol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, and bismaleimides (N, N′-m-phenylene bismaleimide etc.). These crosslinking aids can be used alone or in combination of two or more. The ratio of the cross-linking aid (total amount when a plurality of types are combined) is, for example, 0.01 to 10 parts by mass, preferably 0.05 to 8 parts by mass, based on 100 parts by mass of the rubber component, in terms of solid content. Good to do.

  Further, the rubber composition may contain short fibers, if necessary. As the short fibers, cellulose fibers (cotton, rayon, etc.), polyester fibers (PET, PEN fibers, etc.), aliphatic polyamide fibers (6 nylon fibers, 66 nylon fibers, 46 nylon fibers, etc.), aromatic polyamide fibers ( p-aramid fiber, m-aramid fiber and the like), vinylon fiber, polyparaphenylene benzobisoxazole fiber and the like. These short fibers can be used alone or in combination of two or more. Further, these short fibers may be subjected to a conventional adhesion treatment or surface treatment, for example, a treatment with an RFL solution or the like, in order to enhance dispersibility and adhesiveness in the rubber composition. The ratio of the short fibers (the total amount when a plurality of types are combined) is, for example, 1 to 50 parts by mass, preferably 5 to 40 parts by mass, and more preferably 10 to 35 parts by mass with respect to 100 parts by mass of the rubber component. Good.

  Further, the rubber composition may contain, if necessary, conventional additives such as a vulcanization aid, a vulcanization retarder, a reinforcing agent (carbon black, silicon oxide such as hydrous silica), a filler (clay, carbonic acid). Calcium, talc, mica, etc., metal oxides (zinc oxide, magnesium oxide, calcium oxide, barium oxide, iron oxide, copper oxide, titanium oxide, aluminum oxide, etc.), plasticizers (paraffin oil, naphthene oil, process) Oils, etc.), processing agents or processing aids (stearic acid, stearic acid metal salts, waxes, paraffins, fatty acid amides, etc.), antioxidants (antioxidants, heat antioxidants, flex crack inhibitors, Ozone deterioration inhibitor, etc.), colorant, tackifier, coupling agent (silane coupling agent, etc.), stabilizer (ultraviolet absorber, antioxidant) Antiozonants, thermal stabilizers), lubricants (graphite, molybdenum disulfide, ultrahigh molecular weight polyethylene, etc.), a flame retardant, an antistatic agent and the like. The metal oxide may act as a crosslinking agent. These additives can be used alone or in combination of two or more kinds. The proportion of these additives can be selected from a conventional range according to the type, and for example, the proportion of the reinforcing agent (carbon black, silica, etc.) is 10 to 200 parts by mass with respect to 100 parts by mass of the rubber component ( 20 to 150 parts by mass), the proportion of metal oxides (zinc oxide, etc.) is 1 to 15 parts by mass (preferably 2 to 10 parts by mass), and the proportion of plasticizers (oils such as paraffin oil) is 1 to 30 parts by mass (preferably 5 to 25 parts by mass), and the ratio of the processing agent (stearic acid, etc.) may be 0.1 to 5 parts by mass (preferably 0.5 to 3 parts by mass).

(Expansion layer 3)
The extension layer 3 may be formed of the same rubber composition (rubber composition containing a rubber component such as ethylene-α-olefin elastomer) as that of the compression layer 4, or may be formed of cloth (reinforcing cloth) such as canvas. Good. Examples of the reinforcing cloth include cloth materials such as woven cloth, wide-angle sail cloth, knitted cloth, and non-woven cloth. Among these, a woven fabric woven in the form of a plain weave, a twill weave, a satin weave, a wide-angle canvas or a knitted fabric having an intersection angle of warp and weft of about 90 ° to 130 ° is preferable. As the fibers forming the reinforcing cloth, the same fibers as the short fibers can be used. The reinforcing cloth may be treated with an RFL solution (immersion treatment or the like) and then subjected to coating treatment or the like to be a rubber-attached sailcloth.

  The extension layer 3 is preferably formed of the same rubber composition as the compression layer 4. As the rubber component of the rubber composition of the extension layer 3, a rubber of the same type or the same type as the rubber component of the compression layer 4 is often used. Further, the proportion of additives such as a vulcanizing agent or a crosslinking agent, a co-crosslinking agent, and a vulcanization accelerator can be selected from the same range as that of the rubber composition of the compression layer 4.

  The rubber composition of the extension layer 3 may contain the same short fibers as those of the compression layer 4 in order to suppress the generation of abnormal noise due to the adhesion of the back rubber when driving the back surface. The form of the short fibers may be linear or partially bent (for example, the milled fiber described in JP2007-120507A). When the V-ribbed belt 1 is running, cracks may occur in the stretching layer 3 in the circumferential direction of the belt and the V-ribbed belt 1 may be torn, but this is prevented by orienting the short fibers in the belt width direction or in a random direction. be able to. Further, in order to suppress the generation of abnormal noise when driving the back surface, a concavo-convex pattern may be provided on the surface of the stretching layer 3 (back surface of the belt). The concavo-convex pattern may, for example, be a knitted fabric pattern, a woven fabric pattern, a woven woven fabric pattern, an embossed pattern (for example, a dimple shape), and its size and depth are not particularly limited.

(Core 5)
The core wire 5 is not particularly limited, and polyester fiber (polybutylene terephthalate fiber, polyethylene terephthalate fiber, polytrimethylene terephthalate fiber, polyethylene naphthalate fiber, etc.), aliphatic polyamide (nylon) fiber (6 nylon fiber, 66 nylon) Fiber, 46 nylon fiber, etc.), aromatic polyamide (aramid) fiber (copolyparaphenylene / 3,4'oxydiphenylene / terephthalamide fiber, poly-p-phenylene terephthalamide fiber, etc.), polyarylate fiber, glass fiber, A cord formed of carbon fiber, PBO fiber, or the like can be used. These fibers can be used alone or in combination of two or more. Further, these fibers are appropriately selected according to the expansion coefficient of the flexible jacket 51 described later. For example, when the expansion rate of the flexible jacket 51 is high such that the expansion rate exceeds 2%, polyester fibers having a low elastic modulus (particularly low elastic polybutylene terephthalate fibers), nylon fibers (particularly 66 nylon fibers, 46 nylon fibers) are used. ) Is preferred. This is because with fibers having a high elastic modulus such as aramid fibers and PBO fibers, the fibers cannot be sufficiently expanded even when the flexible jacket 51 expands, and the pitch of the core wires 5 embedded in the V-ribbed belt 1 is increased. This is because the line is not stable and the proper shape of the rib portion 2 is not formed. Therefore, in order to use a fiber having a high elastic modulus, it is preferable to set the expansion coefficient of the flexible jacket 51 to a low value (for example, about 1%).

(Knitted fabric 6: constituent material)
The knitted fabric 6 may be weft knitting or warp knitting. Since the weft knitting is excellent in stretchability, when the knitted fabric 6 is a weft knitting, the knitted fabric 6 can be more easily attached to the friction transmission surface having the unevenness formed by the rib portions 2. As the weft knitted into a single layer, there are a flat knit (textile knitting), rubber knitting, tuck knitting, pearl knitting, and the like, and as the knitted in multiple layers, smooth knitting, interlock knitting, double rib knitting. Hen, single picket, ponchiroma, Milano rib, double jersey, Kanoko (Omokanoko, Urakanoko, double-sided Kanoko) and so on. Examples of knitted single layers include single denby and single cord.Layered knits include half tricot, double denby, double atlas, double chord, and double tricot. .

  Further, as the yarn for knitting the knitted fabric 6, a yarn made of a single type of fiber (single yarn) or a yarn made of a plurality of types of fibers (composite yarn) can be used. These can be used individually, but they are preferably used in combination because different properties can be imparted to the knitted fabric 6. For example, the knitted fabric 6 includes a polyester-based composite yarn and a cellulosic natural spun yarn (for example, cotton yarn). May be organized in. The polyester-based composite yarn is a composite yarn containing polyester fibers and fibers other than polyester fibers. The polyester-based composite yarn may be a textured yarn. The bulky processed thread is a processed thread having a large cross-section by causing the fiber to be crimped (crimping property) or by covering the core thread with another thread. The bulky processed yarns include conjugate yarns, covering yarns, crimped yarns, woolly textured yarns, taslan textured yarns, interlaced textured yarns, and the like. As the polyester-based composite yarns, conjugate yarns or covering yarns are preferable. .

  The conjugate yarn has a cross-sectional structure in which two types of polymers are stuck together in the fiber axis direction, and when heat is applied during manufacturing or processing, crimp occurs due to the difference in shrinkage ratio of both polymers, resulting in a bulky yarn. . For example, a conjugate yarn (PTT / PET conjugate yarn) made of polytrimethylene terephthalate (PTT) and polyethylene terephthalate (PET), or a conjugate yarn (PBT / PET) made of polybutylene terephthalate (PBT) and polyethylene terephthalate (PET). There is a conjugate thread). Further, the covering yarn is a yarn in which the bulk of the cross section of the entire yarn is increased by covering (covering) the periphery of the core yarn with another yarn. For example, covering yarn (PET / PU covering yarn) whose surface is covered with polyethylene terephthalate (PET) or polyurethane (PU) yarn having excellent stretchability, or PU as a core, the surface of which is polyamide (PA) There is a covering thread (PA / PU covering thread) covered with. Of these, the PTT / PET conjugate yarn or PET / PU covering yarn, which is excellent in stretchability and abrasion resistance, is preferable as the polyester-based composite yarn contained in the knitted fabric 6.

  Natural cellulose-based spun yarns include bamboo fiber, sugar cane fiber, seed hair fiber (cotton fiber (cotton linter), kapok, etc.), gin skin fiber (eg, hemp, kozo, mitsumata, etc.), leaf fiber (eg, Manila hemp, New Zealand). Examples of such fibers include cellulose fibers (pulp fibers) derived from natural plants such as hemp), cellulose fibers derived from animals such as wool, silk, ascidian cellulose, bacterial cellulose fibers, and algae cellulose. Of these, cotton fibers are preferable because they are particularly excellent in water absorption.

  The knitting ratio of the cellulosic natural spun yarn is preferably 50 to 95 mass%. Further, the knitted fabric of the knitted fabric 6 may be a single layer or a multilayer, and a multilayered knitted fabric structure is preferable in order to prevent the exudation of rubber in the belt body more reliably.

By knitting the knitted fabric including the bulky processed yarn, the bulkiness of the knitted fabric can be increased. The bulkiness of the knitted fabric 6 is preferably 2.0 cm ³ / g or more, more preferably 2.4 cm ³ / g or more. The upper limit is not particularly limited, for example, 4.0 cm ³ / g or less, or 3.5 cm ³ / g may be less. The bulkiness (cm ³ / g) is obtained by dividing the thickness (cm) of the knitted fabric 6 by the mass per unit area (g / cm ² ). Further, in order to more reliably prevent the rubber of the belt body from seeping out to the friction transmission surface, it is also preferable to provide a bulky layer of the knitted fabric on the friction transmission surface.

  When the knitted fabric 6 has a multi-layered knitted fabric structure, a large amount of cellulosic natural spun yarn having excellent water absorbability in the thickness direction of the knitted fabric 6 is arranged in the layer on the frictional power transmission surface side, whereby The water absorption can be further enhanced. When knitting a multi-layer knitted fabric, knitting one layer with only cellulose-based natural spun yarn or with cellulose-based natural spun yarn and polyester-based composite yarn and the other layer with only polyester-based composite yarn Thus, it is possible to knit a multi-layer knitted fabric in which a large amount of cellulose natural spun yarn is arranged in one layer. By arranging the layer in which a large amount of the cellulosic natural spun yarn is arranged on the friction transmission surface side, it is possible to further enhance the water absorption on the friction transmission surface.

  The knitted fabric 6 may contain or adhere a surfactant or a hydrophilic softening agent as a hydrophilic treatment agent. When the hydrophilic treatment agent is contained in or attached to the knitted fabric 6 as described above, when water droplets are attached to the friction transmission surface (knitted fabric 6), the water droplets are quickly attached to the surface of the hydrophilized knitted fabric 6. The wet film spreads to form a water film, and the cellulose natural spun yarn of the knitted fabric 6 absorbs water to remove the water film on the friction transmission surface. Therefore, the reduction of the friction coefficient of the friction transmission surface in the wet state is further suppressed.

  As the hydrophilic treatment agent, a surfactant or a hydrophilic softening agent can be used. As a method of containing or adhering these hydrophilic treatment agents to the knitted fabric, a method of spraying the hydrophilic treatment agent on the knitted cloth, a method of coating the hydrophilic treatment agent on the knitted cloth, or a hydrophilic treatment of the knitted cloth A method of dipping in the agent can be adopted. When the hydrophilic treatment agent is used as the surfactant, the surfactant is applied to the inner peripheral surface of the cylindrical outer mold in which a plurality of rib molds are engraved on the inner peripheral surface in the belt manufacturing method described later. Then, a method of incorporating a surfactant into the knitted fabric by vulcanizing and molding the belt can also be adopted. Among these methods, the method of immersing the knitted fabric in the hydrophilic treatment agent is preferable because the hydrophilic softening agent can be contained and adhered easily and more uniformly.

  Surfactant is a general term for substances that have a hydrophilic group that is easily compatible with water and a hydrophobic group (lipophilic group) that is easily compatible with oil in the molecule, and works to uniformly mix polar and non-polar substances. In addition to the above, it has the effect of reducing the surface tension to improve the wettability and intervening a surfactant between the substances to reduce the friction at the interface.

  The type of surfactant is not particularly limited, and ionic surfactants, nonionic surfactants and the like can be used. The nonionic surfactant may be a polyethylene glycol type nonionic surfactant or a polyhydric alcohol type nonionic surfactant.

  Polyethylene glycol type nonionic surfactants have a hydrophilic group formed by adding ethylene oxide to a hydrophobic base component having a hydrophobic group such as higher alcohol, alkylphenol, higher fatty acid, polyhydric alcohol higher fatty acid ester, higher fatty acid amide, and polypropylene glycol. It is a given nonionic surfactant.

Examples of higher alcohols as the hydrophobic base component include C _10-30 saturated alcohols such as lauryl alcohol, tetradecyl alcohol, cetyl alcohol, octadecyl alcohol and aralkyl alcohol, and C _10-26 unsaturated alcohols such as oleyl alcohol. It can be illustrated. Examples of alkylphenols include C _4-16 alkylphenols such as octylphenol and nonylphenol.

As the higher fatty acid as the hydrophobic base component, a saturated fatty acid (for example, C _10-30 saturated fatty acid such as myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, lignoceric acid, cerotic acid and montanic acid, preferably C _12-28 saturated fatty acids, more preferably C _14-26 saturated fatty acids, especially C _16-22 saturated fatty acids, etc .; oxycarboxylic acids such as hydroxystearic acid, etc., unsaturated fatty acids (eg oleic acid, erucic acid, erucic acid) , C _10-30 unsaturated fatty acids such as linoleic acid, linolenic acid, and eleostearic acid). These higher fatty acids may be used alone or in combination of two or more.

The polyhydric alcohol higher fatty acid ester is an ester of a polyhydric alcohol and the higher fatty acid, and has an unreacted hydroxyl group. Examples of the polyhydric alcohol include alkanediol (C _2-10 alkanediol such as ethylene glycol, propylene glycol, butanediol), alkanetriol (glycerin, trimethylolethane, trimethylolpropane, etc.), alkanetetraol (pentaerythritol, Examples thereof include diglycerin), alkanehexaol (dipentaerythritol, sorbitol, sorbit, etc.), alkaneoctaol (sucrose, etc.), and their alkylene oxide adducts (C _2-4 alkylene oxide adducts, etc.).

Hereinafter, when "oxyethylene", "ethylene oxide" or "ethylene glycol" is represented by "EO" and "oxypropylene", "propylene oxide" or "propylene glycol" is represented by "PO", polyethylene glycol type non- Specific examples of the ionic surfactant include, for example, poly EO higher alcohol ether (poly EOC _10-26 alkyl ether such as poly EO lauryl ether and poly EO stearyl ether) and C _10-26 such as poly EO poly PO alkyl ether. Higher alcohol-EO-PO adduct; alkylphenol-EO adduct such as poly EO octyl phenyl ether, poly EO nonyl phenyl ether; fatty acid-EO adduct such as poly EO monolaurate, poly EO monooleate, poly EO monostearate ; Glyceri Mono- or di-higher fatty acid esters -EO adduct (glycerin mono- or dilaurate, glycerin mono- or dipalmitate, glyceryl mono- or distearate, EO adducts of glycerin mono- or di-C _10-26 fatty acid esters such as glycerol mono- or dioleate), pentaerythritol Higher fatty acid ester-EO adducts (pentaerythritol distearate-EO adduct and other pentaerythritol mono to tri C _10-26 fatty acid ester-EO adducts, etc.), dipentaerythritol higher fatty acid ester-EO adduct, sorbitol higher Sorbi such as fatty acid ester-EO adduct, sorbit higher fatty acid ester-EO adduct, poly EO sorbitan monolaurate, poly EO sorbitan monostearate, poly EO sorbitan tristearate Fatty acid ester-EO adduct, sucrose higher fatty acid ester-EO adduct and other polyhydric alcohol fatty acid ester-EO adduct; higher alkylamine-EO adduct such as poly EO lauryl amino ether and poly EO stearyl amino ether; Fatty acid amide-EO adducts such as poly EO palm fatty acid monoethanol amide, poly EO lauric acid monoethanol amide, poly EO stearic acid monoethanol amide, poly EO oleic acid monoethanol amide; poly EO castor oil, poly EO hardened castor oil And fats-EO adducts; polyPO-EO adducts (polyEO-polyPO block copolymers, etc.) and the like. These polyethylene glycol type nonionic surfactants can be used alone or in combination of two or more kinds.

  Polyhydric alcohol-type nonionic surfactants are nonionic surfactants in which a hydrophobic group such as a higher fatty acid is bonded to the above polyhydric alcohol (in particular, alkanetriol or alkanehexaol such as glycerol, pentaerythritol, sucrose, and sorbitol). It is an agent. The polyhydric alcohol type nonionic surfactant, for example, glycerin monostearate, glycerin fatty acid ester such as glycerin monooleate, pentaerythritol monostearate, pentaerythritol di-beef tallow fatty acid ester such as pentaerythritol fatty acid ester, Sorbitan monolaurate, sorbitan fatty acid esters such as sorbitan monostearate, sorbitol fatty acid esters such as sorbitol monostearate, sucrose fatty acid esters, alkyl ethers of polyhydric alcohols, fatty acid amides of alkanolamines such as palm fatty acid diethanolamide, Examples thereof include alkyl polyglycoside. These polyhydric alcohol type nonionic surfactants may be used alone or in combination of two or more, and may be used in combination with the polyethylene glycol type nonionic surfactant.

  The ionic surfactants are alkylbenzene sulfonate, α-olefin sulfonate, long chain fatty acid salt, alkane sulfonate, alkyl sulfate, poly EO alkyl ether sulfate ester salt, naphthalene sulfonate formalin condensate, alkyl. It may be an anionic surfactant such as a phosphate, a cationic surfactant such as an alkyltrimethylammonium salt or a dialkyldimethylammonium salt, and an amphoteric surfactant such as an alkylbetaine or an imidazoline derivative.

Preferred surfactants are nonionic surfactants, especially polyethylene glycol type nonionic surfactants (eg, poly EOC _10-26 alkyl ether, alkylphenol-EO adducts, polyhydric alcohol C _10-26 fatty acid ester-EO). It is an adduct etc.).

  The hydrophilic softening agent as the hydrophilizing agent is a softening agent used to impart flexibility to a fibrous member such as a knitted fabric or a woven fabric, to which hydrophilicity is imparted. A general softener has various effects such as suppleness of a fiber member, good slippage, prevention of wrinkles, and prevention of shrinkage. Although the hydrophilic softener is slightly inferior to the surfactant in the pronunciation resistance when the belt is wet, it can improve the flexibility of the knitted fabric, so it can prevent the wrinkle of the knitted fabric and wrap the knitted fabric at the time of manufacturing the belt. There is an effect that the knitted fabric can be easily attached to the frictional transmission surface having the rib portion 2 in which irregularities are formed.

  The hydrophilic softener is not particularly limited, but a polyether-modified silicone softener and a polyester softener can be used. The polyether-modified silicone-based softening agent is a softening agent containing a silicone modified with a hydrophilic polyether group. The polyether-modified silicone softener may be an emulsion in which silicone is dispersed in water together with a surfactant.

  A polyester softener is an emulsion softener in which a hydrophilic polyester resin is dispersed in water together with a surfactant and has a high affinity with polyester fibers, so it is necessary to increase the hydrophilicity of the polyester composite yarn in the knitted fabric. You can

  In the present embodiment, a part of the knitted fabric 6 may contain and adhere the surfactant or the hydrophilic softening agent by a dipping treatment in which the knitted fabric 6 is dipped in the hydrophilic treatment agent. A polyethylene glycol type nonionic surfactant may be used as the surfactant, and the concentration of the treatment liquid may be 0.5 to 30% by mass. As the hydrophilic softening agent, a polyether-modified silicone softening agent and a polyester softening agent may be used, and the concentration of the treatment liquid may be 1 to 10% by mass. The solvent of the treatment liquid containing the hydrophilic treatment agent is not particularly limited, and examples thereof include general-purpose solvents such as water, hydrocarbons, ethers, and ketones. These solvents may be used alone or as a mixed solvent.

  In any case of immersion treatment, the immersion time is not particularly limited. The immersion treatment temperature is not particularly limited, and may be performed at room temperature or under heating. Moreover, you may perform a drying process as needed after an immersion process. The drying treatment may be carried out, for example, while heating at 50 ° C. or higher, preferably 100 ° C. or higher.

  Further, the knitted fabric 6 may be subjected to an adhesive treatment for the purpose of improving the adhesiveness with the rubber composition (the rubber composition forming the surface of the rib portion 2) forming the compression layer 4. Examples of the adhesion treatment of the knitted fabric 6 include dipping treatment in a resin treatment liquid in which an epoxy compound or isocyanate compound is dissolved in an organic solvent (toluene, xylene, methyl ethyl ketone, etc.), resorcin-formalin-latex liquid (RFL liquid). ), And a rubber paste obtained by dissolving the rubber composition in an organic solvent. Other methods of adhesion treatment include, for example, a friction treatment of imprinting the rubber composition on the knitted fabric 6 by passing the knitted fabric 6 and the rubber composition through a calendar roll, a spreading treatment of applying a rubber paste to the knitted fabric 6, A coating treatment or the like in which a rubber composition is laminated on the knitted fabric 6 can also be adopted. By performing the adhesion treatment on the knitted fabric 6 in this manner, the adhesion to the compression layer 4 can be improved, and the knitted fabric 6 can be prevented from peeling off when the V-ribbed belt 1 is running. Further, the abrasion resistance of the rib portion 2 can be improved by performing the adhesion treatment.

(Knitted fabric 6: adhesive region 63 and non-adhesive region 64 of the overlapping portion 62)
The details will be described in the item of the method for manufacturing the V-ribbed belt 1 to be described later. The knitted fabric 6 used in the V-ribbed belt 1 of the present embodiment is obtained by subjecting a long knitted fabric 6 to an adhesive treatment and then an adhesive treatment. The one end of the knitted fabric 6 and the other end are overlapped so as to overlap each other (see FIGS. 4 and 5), and the upper surface side of one end of the knitted fabric 6 and the lower surface side of the other end are bonded to form a tubular knitted fabric. After producing 6, the unvulcanized stretch layer sheet 3S and the unvulcanized compression layer sheet 4S are wound and vulcanized, so that the rib portion 2 serving as the friction transmission surface of the V-ribbed belt 1 is formed. It covers the surface. The knitted fabric 6 may be formed by adhering one end and the other end of a plurality of knitted fabrics, or may be formed by adhering both ends of one knitted fabric.

  Here, as shown in FIG. 3 to FIG. 5, the knitted fabric 6 used in the V-ribbed belt 1 has one end of the long knitted fabric 6 overlapped with the other end thereof, and an overlapped portion 62 bonded to the knitted fabric 62. Have The overlapping portion 62 has a bonding region 63 containing a bonding component that bonds the upper surface side of one end of the knitted fabric 6 and the lower surface side of the other end. In addition to the adhesive region 63, the overlapping portion 62 has a non-adhesive region 64 that does not include an adhesive component and that does not adhere the upper surface side of one end of the knitted fabric 6 and the lower surface side of the other end. Is preferred.

  The overlap length L (the length of the overlapping portion 62 in the belt circumferential direction, which is the length of the overlapping portion in the belt circumferential direction when the ends of the knitted fabric 6 are overlapped so as to overlap each other, 4 and 5) is not particularly limited, but is preferably 2 mm or more and 10 mm or less. If the overlap length L is less than 2 mm, the effect of increasing the strength of the overlap portion 62 may not be sufficient, and conversely, if the overlap length L exceeds 10 mm, the appearance quality may be deteriorated and abnormal noise and tension may vary. There is a concern that such problems will occur.

Below, the aspect of the adhesion area | region 63 and the non-adhesion area | region 64 in the overlap part 62 is illustrated with reference to FIGS. 6-9.
For example, the overlapping portion 62 shown in FIG. 6A includes four circular (dot-shaped) adhesive regions 63 arranged at predetermined intervals in the belt width direction and four adhesive regions in the overlapping portion 62. The non-adhesive region 64 other than 63 is provided, and the upper surface side of one end of the knitted fabric 6 and the lower surface side of the other end thereof are adhered by the adhesive components of the four adhesive regions 63. The number of circular adhesive regions 63 is not limited to four, and may be less than four or more than four. Further, the adhesion region 63 is not limited to the circular shape, and may have a quadrangular shape, a triangular shape, or an elliptical shape.

  Further, in the overlapping portion 62 shown in FIG. 6B, four circular adhesive regions 63 arranged in one row at predetermined intervals in the belt width direction are provided in three rows in the belt circumferential direction, Further, in the overlapping portion 62, the non-adhesive regions 64 other than the adhesive regions 63 are bonded to the upper surface side of one end of the knitted fabric 6 and the lower surface side of the other end by the adhesive component of the twelve adhesive regions 63. In the overlapping portion 62 shown in FIG. 6B, the four circular bonding areas 63 arranged in each row are different from the four bonding areas 63 arranged in adjacent rows in the belt circumferential direction. They are arranged so that they are staggered when viewed. The number of circular adhesive regions 63 arranged in the belt width direction is not limited to four, and may be less than four or more than four. Further, the plurality of adhesion regions 63 arranged in the belt width direction may be provided in two rows in the belt circumferential direction, or may be provided in more than three rows.

  Further, in the overlapping portion 62 shown in FIG. 6C, four quadrangular (corner-dot-shaped) adhesive regions 63 arranged in a row at predetermined intervals in the belt width direction are arranged in the belt circumferential direction. Three rows are provided, and the upper surface of one end of the knitted fabric 6 and the lower surface of the other end of the knitted fabric 6 are formed by the adhesive components of the twelve adhesive regions 63, with the non-adhesive regions 64 other than the adhesive regions 63 in the overlapping portion 62. It is glued. In the overlapping portion 62 shown in FIG. 6C, the four rectangular bonding areas 63 arranged in each row are different from the four bonding areas 63 arranged in adjacent rows in the belt circumferential direction. They are arranged so that they are staggered when viewed. The bonding area 63 is not limited to the quadrangular shape, but may be a triangular shape or an elliptical shape.

  Further, in the overlapping portion 62 shown in FIG. 7A, a plurality of adhesive regions 63 and a plurality of non-adhesive regions 64 are arranged in a checkered pattern, and the knitted fabric is formed by the adhesive components of the plurality of adhesive regions 63. The upper surface side of one end of 6 and the lower surface side of the other end are bonded.

  In the overlap portion 62 shown in FIG. 7B, the adhesive regions 63 are arranged in a wavy (or lightning-like) shape, and the adhesive component of the wavy adhesive regions 63 causes the upper surface side of one end of the knitted fabric 6 to be located. And the lower surface side of the other end are bonded.

  Further, in the overlap portion 62 shown in FIG. 8A, all the portions where the upper surface side of one end of the knitted fabric 6 and the lower surface side of the other end overlap each other are used as the adhesion region 63. In this case, the overlapping portion 62 does not have the non-bonding area 64.

  Further, in the overlapping portion 62 shown in FIG. 8B, two rows of adhesive regions 63 are continuously arranged in the belt width direction, and a non-adhesive region 64 is arranged between the two rows of adhesive regions 63. The upper surface of one end of the knitted fabric 6 and the lower surface of the other end of the knitted fabric 6 are adhered to each other by the adhesive components of the two rows of adhesive regions 63. The overlapping portion 62 is not limited to the two rows of the adhesive areas 63, and may have one row or three or more rows of the adhesive areas 63 in the belt width direction.

  Further, in the overlap portion 62 shown in FIG. 8C, four circular non-bonding regions 64 arranged in one row at a predetermined interval in the belt width direction are provided in three rows in the belt circumferential direction. Further, in the overlapping portion 62, the areas other than the non-adhesive area 64 are used as the adhesive area 63, and the upper surface side of one end of the knitted fabric 6 and the lower surface side of the other end are adhered by the adhesive component of the adhesive area 63. In the overlapping portion 62 shown in FIG. 8C, the four circular non-adhesion regions 64 arranged in each row are different from the four non-adhesion regions 64 arranged in adjacent rows with respect to the belt circumference. They are arranged so that they are staggered when viewed from the direction. The number of circular non-adhesive regions 64 arranged in the belt width direction is not limited to four, and may be less than four or more than four. Further, the plurality of non-adhesion regions 64 arranged in the belt width direction may be provided in less than three rows or in more than three rows in the belt circumferential direction.

  Further, in the overlapping portion 62 shown in FIG. 9A, the adhesive regions 63 (5 rows) and the non-adhesive regions 64 (6 rows), which are continuously arranged in the belt circumferential direction, are alternately arranged. The upper surface of one end of the knitted fabric 6 and the lower surface of the other end of the knitted fabric 6 are bonded to each other by the bonding component of the bonding region 63. In addition, the overlapping portion 62 is not limited to the adhesive regions 63 of five rows, but may have the adhesive regions 63 of four lines or less in the belt circumferential direction, or the adhesive regions 63 of six lines or more. Good.

  Further, in the overlap portion 62 shown in FIG. 9B, five adhesive regions 63 and six non-adhesive regions 64, which are continuously arranged obliquely with respect to the belt circumferential direction, are alternately arranged. The upper surface of one end of the knitted fabric 6 and the lower surface of the other end of the knitted fabric 6 are bonded to each other by the bonding component of the bonding region 63. Note that the overlapping portion 62 is not limited to the five adhesive regions 63, and may have four or less adhesive regions 63 arranged obliquely continuously with respect to the belt circumferential direction, or six adhesive regions 63. You may have the said adhesion area | region 63.

The effects of the modes of the adhesive region 63 and the non-adhesive region 64 in the overlapping portion 62 will be described below.
When the knitted fabric 6 that covers the surface of the compression layer 4 of the V-ribbed belt 1 is joined by abutting without the overlap portion 62, it is difficult to sufficiently increase the strength of the joined portion of the knitted fabric 6, and the joined portion is difficult. A crack is generated in the knitted fabric, and the knitted fabric 6 is easily separated from the surface of the compression layer 4. Even if the knitted fabric 6 has the overlapping portion 62, if the adhesive region 63 is not provided, the strength of the joint portion of the knitted fabric 6 is not sufficient with only the adhesive component contained in the knitted fabric 6, and The knitted fabric 6 is easily separated from the surface of the compression layer 4. Therefore, in the overlapping portion 62, an adhesive region 63 for adhering the upper surface side of one end of the knitted fabric 6 and the lower surface side of the other end is provided to reinforce the joint portion, so that the knitted fabric 6 has a surface of the compression layer 4. It is possible to make it difficult to peel off from.

  Further, as shown in FIG. 8A, when the entire overlap portion 62 where one end of the knitted fabric 6 overlaps with the other end is the adhesive region 63 and the non-adhesive region 64 does not exist, Since the cloth 6 is strongly restrained, the elasticity of the knitted cloth 6 is reduced. As a result, when the V-ribbed belt 1 is bent, stress is concentrated on the joint portion of the overlap portion, and cracks are likely to occur in the compression layer 4. Therefore, by providing the non-adhesive region 64 together with the adhesive region 63 in the overlapping portion 62, the stress concentration is relaxed while the adhesive force between one end of the knitted fabric 6 and the other end is made sufficient, and compression is performed. Generation of cracks in the layer 4 can be suppressed. As a result, the life of the V-ribbed belt 1 is improved.

  In addition, as in the overlapping portion 62 shown in FIGS. 6A to 6C, FIGS. 7A and 7B, and FIGS. 9A and 9B, the adhesion region 63 is a belt. If the non-adhesive regions 64 are arranged continuously in the width direction, the non-adhesive regions 64 are always arranged in the belt width direction in which the adhesive regions 63 are arranged (the adhesive regions 63 and the non-adhesive regions 64 are (Alternatively arranged in the belt width direction), at a specific position in the belt circumferential direction of the overlap portion 62, stress concentration is mitigated over the entire belt width direction, and the generation of cracks in the compression layer 4 is suppressed. be able to.

  Further, as in the overlap portion 62 shown in FIG. 7A, the adhesive regions 63 and the non-adhesive regions 64 are alternately arranged in a checkered pattern, so that the overlapping portion 62 in the belt circumferential direction is It is possible to mitigate the concentration of stress over the entire belt width direction at a specific location and suppress the occurrence of cracks in the compression layer 4.

  Further, as in the overlap portion 62 shown in FIG. 7B, since the adhesive region 63 is arranged in a wavy or lightning pattern, the adhesive region 63 and the non-adhesive region 64 are formed in the overlap portion 62. It is possible to relieve the concentration of stress over the entire belt width direction at specific positions in the belt circumferential direction of the overlapping portions 62 that are alternately arranged, and suppress the occurrence of cracks in the compression layer 4.

  In addition, the overlapping portion 62 shown in FIGS. 6A to 6C, FIGS. 7A and 7B, 8B, and 9A and 9B is bonded. The total area of the region 63 is preferably 10 to 50% of the area of the overlapping portion 62. If the total area of the bonding region 63 is less than 10% of the area of the overlapping portion 62, the strength of the bonding portion of the overlapping portion 62 of the knitted fabric 6 cannot be sufficiently increased and cracks occur at the bonding portion. Then, the knitted fabric 6 may peel off from the surface of the compression layer 4. On the other hand, when the total area of the adhesion region 63 is larger than 50% of the area of the overlapping portion 62, the knitted fabric 6 is constrained more than necessary, the stretchability of the knitted fabric 6 decreases, and the V-ribbed belt 1 At the time of bending, stress concentrates on the joint portion of the overlap portion, and cracks are likely to occur in the compression layer 4. Therefore, by setting the total area of the adhesive region 63 to 10 to 50% of the area of the overlapping portion 62, the strength of the joint portion of the overlapping portion 62 is sufficiently increased and the stretchability of the knitted fabric 6 is also maintained. Thus, it is possible to prevent peeling of the knitted fabric 6 from the surface of the compression layer 4 and generation of cracks in the compression layer 4 in a balanced manner.

(Adhesive component of adhesive area 63)
As the adhesive component of the adhesive region 63, a rubber component or a thermoplastic elastomer can be mainly used.

  As an example of the rubber component serving as the adhesive component of the adhesive region 63, the rubber component described as the rubber component forming the compression layer 4 can be used. In particular, by using a rubber component of the same type (particularly the same) as the rubber component forming the compression layer 4, the adhesion region 63 can be similarly deformed as the compression layer 4 is deformed, so that stress concentration can be relaxed. preferable. In particular, it is preferable to use the rubber composition for forming the compression layer 4 as it is as an adhesive component because it is not necessary to prepare a new rubber composition for the adhesive component of the adhesive region 63.

  Since the adhesive component of the adhesive region 63 is disposed in the overlapping portion 62 of the knitted fabric 6, it is preferable that the adhesive component has a small thickness, and specifically, it is preferably about 50 to 150 μm. As a method of arranging the adhesive region 63 having such a thickness, a method of preparing a sheet of the rubber composition thinly extended to the above thickness in advance or a method of dissolving the rubber composition in a solvent (such as toluene) and applying a rubber paste A method in which the knitted fabric 6 is prepared by applying it, applying a rubber paste, spraying it, and the like can be considered. The method of using the rubber paste requires a time and effort for drying after application and may reduce the productivity, so that it is preferable to prepare a sheet of the rubber composition in advance. As a method for preparing the sheet of the rubber composition, the rubber composition may be dissolved in a solvent to prepare a rubber paste, and the rubber paste may be thinly spread on a release paper and then dried.

  A general-purpose thermoplastic elastomer can be used as an example of the thermoplastic elastomer (thermoplastic resin) serving as the adhesive component of the adhesive region 63, and specifically, polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyurethane, etc. can be used. Can be illustrated. Of these, from the viewpoint that they are easily melted at a relatively low temperature and attached to the knitted fabric 6, and also melted during vulcanization of the V-ribbed belt 1 and penetrated into the knitted fabric 6 to easily improve the adhesive force, A thermoplastic elastomer having a flow starting point (or softening point) of about 100 to 160 ° C. is preferable. In particular, it is preferable to use thermoplastic polyurethane because it does not contain halogen and has excellent adhesive strength and strength. The thermoplastic polyurethane may be an ether type or an ester type, and may be selected in consideration of strength and water resistance. As described above, the production cost of the belt can be reduced by using a highly versatile thermoplastic polyurethane as the thermoplastic elastomer used for the adhesive component of the adhesive region 63.

  As described above, the thermoplastic elastomer serving as the adhesive component of the adhesive region 63 preferably has a flow starting point of 100 ° C. or higher and 160 ° C. or lower. If the flow starting point of the thermoplastic elastomer is less than 100 ° C., the strength of the adhesive region 63 may decrease during use of the V-ribbed belt 1, and the knitted fabric 6 may be easily peeled off. Further, when the flow starting point of the thermoplastic elastomer is 160 ° C. or lower, the thermoplastic elastomer is softened during vulcanization of the V-ribbed belt 1 and the adhesion with the knitted fabric 6 is improved, so that the adhesive force can be improved. On the other hand, when the flow starting point is higher than 160 ° C., the above effect may not be obtained and the adhesive strength may not be sufficiently improved. Therefore, it is preferable to use a thermoplastic elastomer having a flow starting point of 100 ° C. or higher and 160 ° C. or lower in the bonding region 63.

  As a method for attaching the thermoplastic elastomer to the knitted fabric 6, a melted thermoplastic elastomer may be directly attached to the knitted fabric 6 using a general-purpose dispenser (glue gun, hot melt gun) or the like. As described above, when a thermoplastic elastomer is used as the adhesive component of the adhesive region 63, the occurrence of cracks in the compression layer 4 can be suppressed more than when a rubber composition is used as the adhesive component of the adhesive region 63. .

  In addition, as an adhesive component of the adhesive region 63, a thermosetting elastomer (thermosetting resin) and various general-purpose adhesives (reactive adhesives such as acrylic resin, epoxy resin, urethane resin, EVA (ethylene-vinyl acetate resin) ), Solution adhesives such as phenol resins and melamine resins). When a thermosetting elastomer or a solution-based adhesive is used as the adhesive component of the adhesive region 63, the heat applied during the vulcanization treatment can be used to accelerate the curing reaction and solvent removal. It is possible to improve power and simplify the process.

  A rubber composition in which CNF (cellulose nanofiber) is dispersed may be used as the adhesive component of the adhesive region 63. In this case, the durable life can be improved as compared with the case of using a rubber composition in which CNF is not dispersed. Further, as the adhesive component of the adhesive region 63, thermoplastic polyurethane (TPU) in which CNF is dispersed may be used. In this case, the durable life can be improved as compared with the thermoplastic polyurethane in which CNF is not dispersed.

  Here, the CNF used is manufactured by finely unraveling cellulose, which is the main component of the cell wall of a plant, to a nano size. Examples of the raw material cellulose include wood pulp, rice straw, straw and the like. CNF is a cellulose microfibril having a width of about 4 nm (single cellulose nanofiber), a bundle of several single cellulose nanofibers having a width of about 10 to 20 nm, and a bundle of cellulose microfibrils having a width of several tens. It can be classified into microfibrillated cellulose (MFC) of several hundreds nm. Any of these CNFs may be used, or a CNF in which these CNFs are mixed may be used. As CNF, CNF chemically modified to prevent aggregation can be preferably used. Examples of the chemical modification method include TEMPO oxidation and carboxymethylation.

  As a method of dispersing CNF in the rubber composition and TPU, a homogenizer method can be used. Examples of the homogenizer method include an ultrasonic method, a stirring method, and a high pressure method. When CNF is dispersed in the rubber composition, a method may be mentioned in which the rubber composition is dissolved in a solvent to prepare rubber paste, CNF is added to the rubber paste, and then dispersed by a homogenizer method. In the case of dispersing CNF in TPU, a method of adding CNF to heat-melted TPU and then dispersing it by a homogenizer method may be mentioned. Further, an aqueous dispersion liquid in which CNF is dispersed in water may be used. In this case, for example, an aqueous dispersion liquid in which CNF is dispersed in water is applied to the knitted fabric 6 and dried, and then the adhesive component is arranged in the adhesive region 63. Next, the bonding region 63 is hot pressed (100 ° C., 20 seconds) to integrate the CNF and the bonding component.

  Further, the content concentration of CNF in the adhesive component and in the aqueous dispersion is preferably about 0.01% by mass to 2% by mass. This is because if the concentration is less than 0.01% by mass, the adhesive strength will not be sufficiently improved, and if the concentration exceeds 2% by mass, it will be difficult to uniformly disperse CNF.

  As described above, it is preferable to use an adhesive component excluding isocyanate in the adhesive region 63. Isocyanate is impregnated in the knitted fabric 6 in order to improve wear resistance and adhesiveness, and by using an adhesive component different from the isocyanate impregnated in the knitted fabric 6 in the adhesive region 63, It is possible to secure a sufficient adhesive force at the joined portion of the overlapping portion 62, and it is possible to prevent the knitted fabric 6 from peeling from the surface of the compression layer 4 starting from the overlapping portion 62.

(Method for manufacturing V-ribbed belt 1)
Hereinafter, a method for manufacturing the V-ribbed belt 1 will be described. First, the long knitted fabric 6 is bonded. Then, the ends of the knitted fabric 6 subjected to the adhesion treatment are overlapped so that the ends overlap with each other (see FIG. 5: the overlapping portion 62), and the upper surface side of one end of the knitted cloth 6 and the lower surface side of the other end thereof are overlapped. The tubular knitted fabric 6 is produced through the step of adhering through the adhesion region 63 (adhesion step).

  In the adhering step, a rubber composition having the same composition as that of the compression layer 4 is dissolved in a solvent (such as toluene) to prepare a rubber paste, and the prepared rubber paste is used as an adhesion region 63 on the upper surface side of one end of the knitted fabric 6. After applying by applying or spraying, the lower surface side of the other end of the knitted fabric 6 is overlapped with the upper surface side of the one end of the knitted fabric 6, so that the upper surface side of the one end of the knitted fabric 6 and other The lower surface of one end is bonded via the bonding area 63. As a result, the joint portion of the overlapping portion 62 can be reinforced, and the knitted fabric 6 can be made difficult to separate from the surface of the compression layer 4. The prepared rubber paste is applied or sprayed onto the lower surface of one end of the knitted cloth 6, and then the upper surface of the other end of the knitted cloth 6 is attached to the lower surface of the knitted cloth 6. By overlapping on the lower surface side, the lower surface side of one end of the knitted fabric 6 and the upper surface side of the other end may be bonded via the bonding region 63.

  In addition, as another method of the bonding step, a rubber composition sheet having a thickness of 50 to 150 μm is bonded between the upper surface side of one end of the knitted fabric 6 and the lower surface side of the other end of the knitted fabric 6. By disposing as 63, the upper surface side of one end of the knitted fabric 6 and the lower surface side of the other end may be bonded via the bonding region 63. As a result, by disposing the sheet-shaped rubber composition between the upper surface side of one end of the knitted fabric 6 and the lower surface side of the other end of the knitted fabric 6, the sheet-like rubber composition, which is easier to handle than applying or spraying rubber glue, can be obtained. Productivity can be improved. In addition, the thickness of the sheet-shaped rubber composition is set to 50 to 150 μm to secure sufficient adhesiveness, while minimizing the step of the overlapping portion 62 to reduce appearance quality and abnormal noise or tension fluctuation. It is possible to suppress such problems.

  As another method of the bonding step, by arranging the thermoplastic elastomer as a bonding region 63 between the upper surface of one end of the knitted fabric 6 and the lower surface of the other end of the knitted fabric 6 while melting the thermoplastic elastomer. The upper surface side of one end of the knitted fabric 6 and the lower surface side of the other end may be bonded via the bonding region 63. As a result, the bonding area 63 between the upper surface of one end of the knitted fabric 6 and the lower surface of the other end of the knitted fabric 6 can be freely controlled in shape and amount by utilizing the thermoplastic property of the thermoplastic elastomer. Can be placed while.

  Next, as shown in FIG. 10 (a), an unvulcanized stretch layer sheet 3S is wound around an inner mold 52 having a flexible jacket 51 mounted on the outer peripheral surface thereof, and the core wire 5 is placed on the inner layer 52. A molded body 10 is produced by spinning in a spiral shape and further winding the unvulcanized sheet 4S for compression layer and the tubular knitted fabric 6 produced through the above-mentioned bonding step in order. Then, the inner mold 52 wound with the molded body 10 is set concentrically on the inner peripheral side of the outer mold 53 having a plurality of rib molds 53a engraved on the inner peripheral surface. At this time, a predetermined gap is provided between the inner peripheral surface of the outer mold 53 and the outer peripheral surface of the molded body 10.

  Next, as shown in FIG. 10B, the flexible jacket 51 is expanded toward the inner peripheral surface of the outer mold 53 at a predetermined expansion rate (for example, 1 to 6%) to compress the molded body 10. The layer sheet 4S and the knitted fabric 6 are press-fitted into the rib mold 53a of the outer mold 53, and vulcanization treatment (for example, 160 ° C., 30 minutes) is performed in that state.

  Finally, as shown in (c) of FIG. 10, the inner mold 52 is extracted from the outer mold 53, the vulcanized rubber sleeve 10A having the plurality of ribs 2 is released from the outer mold 53, and then a cutter is used. The vulcanized rubber sleeve 10A is cut into a predetermined width along the circumferential direction to finish the V-ribbed belt 1. The method for manufacturing the V-ribbed belt 1 is not limited to the above method, and other known methods disclosed in, for example, Japanese Patent Application Laid-Open No. 2004-82702 may be used.

(Other embodiments)
Although the V-ribbed belt 1 has been described as an example of the friction transmission belt in the above-described embodiment, the present invention can be applied to a flat belt, a V-belt, or the like as long as it is a friction transmission belt.

  Next, the V-ribbed belts according to Examples 1 to 8 and Comparative Examples 1 and 2 having the overlapping portions bonded in the bonding region shape shown in FIGS. 12 and 13 were manufactured, and the durability test was performed.

  Materials and configurations of the V-ribbed belts according to Examples 1 to 8 and Comparative Examples 1 and 2 will be described below.

  Table 1 shows the structures of the rubber compositions used as the stretch layer, the compression layer and the adhesive component in the adhesive region of the V-ribbed belts according to Examples 1 to 8 and Comparative Examples 1 and 2.

ＥＰＤＭポリマー：デュポン・ダウエラストマージャパン社製、「ノーデルＩＰ３６４０」
パラフィン系オイル：出光興産（株）製、「ダイアナプロセスオイル」
老化防止剤：精工化学（株）製、「ノンフレックスＯＤ３」
有機過酸化物：化薬アクゾ（株）製、「パーカドックス１４ＲＰ」
圧縮層用ゴム組成物硬度：８７度 (Rubber composition constituting the stretching layer, the compression layer and the adhesive component of the adhesive region)

EPDM polymer: "Nodell IP3640" manufactured by DuPont Dow Elastomer Japan Ltd.
Paraffin oil: "Diana Process Oil" manufactured by Idemitsu Kosan Co., Ltd.
Anti-aging agent: "Nonflex OD3" manufactured by Seiko Chemical Co., Ltd.
Organic peroxide: Kayaku Akzo Co., Ltd., "Perkadox 14RP"
Rubber composition hardness for compression layer: 87 degrees

(Adhesive component of adhesive area)
As the thermoplastic resin for the adhesive component in the adhesive region, "E780MSTJ" manufactured by Nippon Miractolan Co., Ltd., an ester thermoplastic polyurethane, a hardness of 80 degrees, and a flow starting temperature of 120 ° C were used.

(Core wire)
An aramid cord having a configuration of 1100 dtex / 1 × 4 was used for the core wire, and RFL treatment and overcoat treatment with rubber glue were performed.

(Knitted fabric)
The knitted fabric was knitted with cotton spun yarn (40 count, 1 yarn) as a water-absorbent fiber and PTT / PET conjugate composite yarn (fineness 84 dtex) as a second fiber, and the knitting structure was a weft knitting ( A kanoko (two layers) knitted fabric (fiber member) was used. Then, the heat-reactive isocyanate (“Elastron BN-27” manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., dissociation temperature 180 ° C., solid content concentration 30 mass%) was diluted with water so that the solid content concentration became 5 mass%. The above knitted fabric was dipped in the dipping solution for 10 seconds and then dried at 100 ° C. for 5 minutes to prepare a knitted fabric (fiber member) impregnated with the heat-reactive isocyanate.

(Structures of V-ribbed belts according to Examples 1-8 and Comparative Examples 1-2)
Hereinafter, the configuration of the V-ribbed belt having the overlapping portions bonded in the bonding region shapes according to Examples 1 to 8 and Comparative Examples 1 and 2 will be described with reference to FIGS. 12 and 13.

(Example 1)
The overlap length L was set to 8 mm, and the overlap portion was reinforced with the adhesive region. As the rubber composition used in the adhesion region, a rubber composition punched out in a circular shape having a diameter of 2 mm from a tape-shaped rubber composition obtained by thinly molding the rubber composition for an adhesive component in Table 1 to a thickness of 80 μm in an overlapping portion. They were evenly dispersed and arranged. The ratio of the area occupied by the adhesive region (the total area where the circular rubber compositions are arranged) and the area occupied by the non-adhesive region, which is the region excluding the adhesive region in the overlapping portion, is 25% and 75%, respectively. there were. Then, the overlapping portion was pressure-bonded with a roller to form a knitted fabric having a bonded portion adhered at the overlapping portion. Then, a V-ribbed belt according to Example 1 of 3PK1200 (rib shape: K shape, number of ribs 3, circumference length 1200 mm) was obtained by the manufacturing method shown in the above embodiment (corresponding to the shape of the bonding area in FIG. 6B). ).

(Example 2)
The V-ribbed belt according to the second embodiment is the same as that of the first embodiment except that the overlap length L is 4 mm, and the ratios of the area occupied by the bonded area and the area occupied by the non-bonded area are 15% and 85%, respectively. (Corresponding to the shape of the bonding area in FIG. 6A).

(Example 3)
The V-ribbed belt according to Example 3 has an overlap length L of 8 mm, and a tape-shaped rubber composition having a width of 8 mm is arranged in the overlap portion to form a rubber composition that becomes an adhesive region in the entire overlap portion. It is the same as Example 1 except that it is arranged (corresponding to the shape of the bonding area in FIG. 8A).

(Example 4)
In Example 4, instead of the rubber composition used in Example 1 as the adhesive component of the adhesive region, thermoplastic polyurethane (TPU) was applied to the knitted fabric in the form of circular dots having a diameter of 2 mm while melting with a dispenser. A V-ribbed belt having an adhesive area 25% (non-adhesive area 75%) reinforced with thermoplastic polyurethane was obtained in the same manner as in Example 1 (corresponding to the adhesive area shape in FIG. 6B).

(Example 5)
The V-ribbed belt according to Example 5 is similar to Example 2 except that the overlap length L is 4 mm and the adhesive component used in the adhesive region is thermoplastic polyurethane (the adhesive region in FIG. 6 (a)). Equivalent to the shape).

(Example 6)
In the V-ribbed belt according to Example 6, the overlap length L was 8 mm, thermoplastic polyurethane was used as the adhesive component in the adhesive region, and this thermoplastic polyurethane was adhered in a wavy line shape (line width of about 2 mm). The area of the adhesive region in this case was about 40% (the area of the non-adhesive region was about 60%) (corresponding to the shape of the adhesive region in FIG. 7B).

(Example 7)
In Example 7, as an adhesive component in the adhesive region, 0.1% by mass of CNF (“Sunrose SLD-F1” manufactured by Nippon Paper Industries Co., Ltd., carboxymethyl) was added to the rubber composition for an adhesive component used in Example 1. CNF (powdered form, purity of 99% or more) was used in the same manner as in Example 1 except that a rubber composition in which a CNF-dispersed rubber composition was dispersed was used. % (Non-bonding area 75%) was obtained (corresponding to the shape of the bonding area in FIG. 6B).

(Example 8)
In Example 8, 0.1% by mass of CNF (“Sunrose SLD-F1” manufactured by Nippon Paper Industries Co., Ltd., carboxymethylated CNF) was added to the thermoplastic polyurethane used in Example 4 as an adhesive component in the adhesive region. (Powdered form), purity 99% or more) was used in the same manner as in Example 4 except that the thermoplastic polyurethane in which the homogenizer method was dispersed was used. A V-ribbed belt having a bonding area of 75%) was obtained (corresponding to the bonding area shape of FIG. 6B).

(Comparative Example 1)
The V-ribbed belt according to Comparative Example 1 is a belt in which one end of the knitted fabric and the other end thereof are joined by ultrasonic welding by butting so that the ends of the knitted fabric do not overlap each other, and the overlapping portion is also a bonding region. Is not present (see FIG. 13).

(Comparative example 2)
The V-ribbed belt according to Comparative Example 2 has an overlapping portion having an overlapping length L of 8 mm, but has a configuration in which there is no adhesive region (the non-adhesive region is 100%) (see FIG. 13).

(Durability test method)
The endurance test was conducted by using a multi-axis running test machine in which a driving pulley (Dr.), an idler pulley (Id), a driven pulley (Dn), and a tension pulley (Ten) each having a diameter of 50 mm were arranged in the layout shown in FIG. It was done using. Specifically, each V-ribbed belt of 3PK1200 (rib shape: K type, number of ribs 3, perimeter 1200 mm) is hung on each pulley of the multi-axis running tester, and the rotation speed of the drive pulley is 5600 rpm, and the driven pulley and The idler pulley was unloaded and the belt tension was 294 N / 3 ribs. The test temperature (ambient temperature) was set to 100 ° C., and the presence or absence of peeling of the knitted fabric or cracks in the rib rubber was confirmed with an upper limit of 200 hours. The results of the durability test are shown in FIGS. 12 and 13.

(Consideration of durability test results)
In Comparative Example 1 in which one end of the knitted fabric is joined to the other end by conventional ultrasonic welding, the elasticity of the knitted fabric in the joined part is reduced and stress concentrates. The life was 72 hours. Further, in Comparative Example 2 in which the adhesive region does not exist in the overlap portion, there was a problem that the knitted fabric was separated from the rib surface in a short time of 15 hours.

  On the other hand, Examples 1 to 8 having the overlap portion and the adhesion region in the joined portion of the knitted fabric had a life of 100 hours or more in the durability test and showed the effect of suppressing the occurrence of peeling and cracks. Example 3 is an example in which a rubber composition that serves as an adhesion region is arranged over the entire overlap portion to reinforce, but as compared with Examples 1 and 2, the time until cracking was short. It is considered that this is because stress was concentrated on the joint portion of the overlap portion when the V-ribbed belt was bent because the stretchability of the knitted fabric was hindered by the reinforcement of the adhesive component in the adhesive region. It is considered that the life can be further extended by adopting a configuration in which the belt has both the adhesive region and the non-adhesive region in the overlapping portion as in the first and second embodiments.

  Examples 4 to 6 are examples in which a thermoplastic elastomer was used as the adhesive component in the adhesive region, but none of them showed peeling or cracking at the time of 200 hours of the durability test, and the rubber composition was used as the adhesive component in the adhesive region. The results are better than those obtained by using. Although the reason why good results are obtained with the thermoplastic elastomer is not clear, it is considered that the bonding strength and the stress dispersion are well balanced.

  Example 7 is an example in which a rubber composition in which CNF is dispersed as an adhesive component in the adhesive region is used, but the durability test life is improved as compared with Example 1. In addition, Example 8 is an example in which CNF-dispersed thermoplastic polyurethane is used as an adhesive component in the adhesive region, but the durability test life is improved as compared with Example 4. This is because by adding CNF to the adhesive component in the adhesive region, the CNF enters the fibers of the knitted fabric while being integrated with the adhesive component, and the CNF and the fibers of the knitted fabric are entangled with each other, so that the knitted fabric and the adhesive component are It is considered that this is because the adhesive strength of

1 V-ribbed belt 2 Rib portion 3 Stretching layer 4 Compression layer 5 Core wire 6 Knitted fabric 62 Overlap portion 63 Adhesion region 64 Non-adhesion region 10 Molded body 21 Drive pulley 22 Driven pulley 23 V-shaped groove 51 Flexible jacket 52 In Mold 53 Outer mold 53a Rib type L Overlap length

Claims (15)

A friction transmission belt having a compression layer and a knit fabric,
The surface of the compression layer is covered with the knitted fabric,
The knitted fabric has an overlap portion in which one end of the knitted fabric and the other end overlap with each other,
The overlap portion has an adhesive region containing an adhesive component for adhering one end and the other end of the knitted fabric, and a non-adhesive region where one end and the other end of the knitted fabric are not adhered. belt. Having a plurality of the adhesive regions,
The friction transmission belt according to claim 1 , wherein the adhesive regions are discontinuously arranged in the belt width direction. Having a plurality of the adhesive regions,
Having a plurality of the non-adhesive regions,
The friction transmission belt according to claim 1 , wherein the plurality of adhesion regions and the plurality of non-adhesion regions are arranged in a checkered pattern. The friction transmission belt according to claim 1 , wherein the adhesion region is wavy or lightning-shaped. The friction transmission belt according to any one of claims 1 to 4 , wherein a total area of the adhesion region is 10 to 50% of an area of the overlapping portion. The knitted fabric, the isocyanate is impregnated, friction transmission belt according to any one of claims 1 to 5. The friction transmission belt according to any one of claims 1 to 6 , wherein one end and the other end of the knitted fabric are bonded by an adhesive component excluding isocyanate in the bonding region. The friction transmission belt according to claim 7 , wherein the adhesive component includes a thermoplastic elastomer. The friction transmission belt according to claim 8 , wherein the thermoplastic elastomer is thermoplastic polyurethane. The friction transmission belt according to claim 8 or 9 , wherein a flow starting point of the thermoplastic elastomer is 100 ° C or higher and 160 ° C or lower. The adhesive component comprises a cellulose nanofiber, friction transmission belt according to any one of claims 1 to 10. The friction transmission belt according to any one of claims 1 to 11 , wherein a length of the overlapping portion in a belt circumferential direction is 2 mm or more and 10 mm or less. The surface of the compression layer is covered with a knitted fabric, and the knitted fabric has an adhesive region containing an adhesive component for adhering one end and the other end of the knitted fabric, and one end of the knitted fabric and the other end thereof are adhered to each other. A method of manufacturing a friction transmission belt , which has an overlapping portion with a non-adhesive region ,
A rubber paste prepared by dissolving a rubber composition in a solvent is applied or sprayed to at least one of the adhesive regions on the upper side of one end of the knitted fabric and the lower side of the other end of the knitted fabric. Transmission belt manufacturing method. A method for manufacturing a friction transmission belt, wherein the compression layer surface is covered with a knitted fabric having an overlapping portion in which one end and the other end overlap.
A method for manufacturing a friction transmission belt, comprising a step of disposing a sheet of a rubber composition having a thickness of 50 to 150 μm between an upper side of one end of the knitted fabric and a lower side of the other end of the knitted fabric. The surface of the compression layer is covered with a knitted fabric, and the knitted fabric has an adhesive region containing an adhesive component for adhering one end and the other end of the knitted fabric, and one end of the knitted fabric and the other end thereof are adhered to each other. A method of manufacturing a friction transmission belt , which has an overlapping portion with a non-adhesive region ,
A method for manufacturing a friction transmission belt, which comprises the step of disposing a melted thermoplastic elastomer in the bonding region between an upper side of one end of the knitted fabric and a lower side of the other end of the knitted fabric.

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